I Can not able to merge PDF FIles has more than one page

I used your package for merging two pdf files.

I can't able to merge pdf files. 

EX:
$filepath1 = 'file1';
$filepath2 = 'file2';

**Success:**
If both file have single page it's working fine.

**Fail:**
If anyone pdf have more than one page doesn't work.

**Need:**
How to merge nore than one page in all PDF files.

